This invention relates to improved resins and polymers for use in and as exterior architectural house paints and coatings, particularly coatings having utility over weathered, chalky substrates such as brick, wood, vinyl and aluminum siding. A chalky substrate is one in which the elements (sun, rain, snow, heat, etc.) have degraded the paint film's integrity to such a degree that it breaks down and a fine powder develops that resides on the surface of the structure or dwelling. This powder consists of pigment, binder, additives, etc. which due to the degradation of the paint film are no longer part of a coherent film. Such a degraded film does not provide good protection for the substrate below. Furthermore, such chalky substrates are generally not preferred surfaces for applying a new layer of paint since the chalk will adversely affect the adhesion characteristics of the new paint to the substrate.
U.S. Pat. No. 4,722,965 discloses a latex polymer comprising a major amount of an alkyl acrylate and/or alkyl methacrylate and a minor amount of a secondary amine, which latex polymer can be blended with vinyl acetate/acrylic copolymer coatings to form a latex coating composition with improved chalk adhesion properties.
European Patent Application 94309136.3 discloses the use of a polymeric blend of a latex, an acid-functional alkali-soluble resin and an aminosilane in order to provide adhesion of coatings over chalky substrates.
U.S. Pat. No. 5,202,378 discloses an exterior latex paint having improved chalk adhesion wherein the latex paint is based on a polymeric film-forming binder containing minor amounts of copolymerized fatty acid acrylate or methacrylate such as lauryl or stearyl methacrylate.
Presently, there are a number of commercially available latex and alkyd paints that claim to be suitable for use on chalky substrates. All presently available coatings have shortcomings, either in adhesion properties or in other paint properties. The present invention offers better adhesion over chalky substrates and other substrates than the presently available coatings.